With the rapid developments of radiation-based imaging technologies including, for example, computed tomography (CT), positron emission tomography (PET), magnetic resonance imaging (MRI), and the expansion of their new clinical and industrial applications, the accuracy of the diagnosis may pose a challenge.
In one respect, a CT image and/or an MRI image may be combined with a PET image to provide a relatively thorough information of the tested subject. Also, in another respect, methods and apparatus may be provided to compare results of two or more medical image scans acquired at different time points, which may enable an accurate analysis of the changes in, for example, a lesion area. Such methods and apparatus may facilitate the interpretation of the images, and increase the accuracy of the diagnosis.